The use of medical balloons and balloon catheters is gaining widespread use in the medical field for effecting a variety of medical procedures, such as angioplasty, vascular dilatation, valvuloplasty, vascular occlusion, deployment and retrieval of implantable medical devices and for other clinical applications. There are a number of technical and clinical considerations involved with the design and use of medical balloons including, for example, visibility of the balloon during the medical procedure and also maintaining the position of the balloon in the patient's vasculature. Such medical balloons are typically made of a thin-walled material in order to ensure that the balloon can be wrapped to a very small profile and also to optimize the flexibility of the balloon. As a result of this, medical balloons of this nature tend to be very difficult to see by conventional imaging techniques when they are located within a patient. In light of this, it is known to inflate such medical balloons with an imaging agent, typically a radiopaque material. However, such materials tend to be relatively viscous compared to traditional inflating fluids, such as saline solution, resulting in greater inflating and deflation times of the balloon and also restricting the size of the inflation/deflation lumen which can be used for that balloon. Moreover, these radiopaque fluids tend not to be particularly biocompatible, leading to potential difficulties should the balloon burst and release fluid into the patient's blood system.
With respect to positioning of the balloon within the patient's vasculature, since medical balloons are typically inflated until they are fully stretched, they tend to have a smooth outer surface. The result of this is that they tend to be relatively slippery. A slippery balloon can be difficult to position accurately and to hold in position within a patient's vasculature, particularly given the fluid pressure within a patient's vessel. Migration of the balloon can lead to medical complications. Attempts have been made to roughen the outer surface of a medical balloon. However, these attempts have not always been successful as surface features tend to flatten as the balloon is stretched during its inflation.
Examples of balloon catheters can be found in U.S. Pat. No. 7,758,572 and US 2010/0130926.